1. Field of the Invention
The present invention relates to a radiographic imaging apparatus and electronic cassette. More particularly, the present invention relates to a radiographic imaging apparatus and electronic cassette in which radiographic imaging can be performed continuously and smoothly in a workflow without unwanted interruption.
2. Description Related to the Prior Art
A radiographic imaging apparatus or system, or X-ray imaging apparatus or system is known in the field of the medical diagnosis for imaging of a patient body by use of radiation or X-rays. The radiographic imaging apparatus includes a radiographic imaging device (apparatus) or X-ray imaging device (apparatus), and a console device or user terminal device. The radiographic imaging device detects (generates) a radiation image according to X-rays transmitted through the patient body or object. The console device communicates with the radiographic imaging device for transmitting various data and the radiation image.
A sensor panel or detection panel is incorporated in the radiographic imaging device, for example, a flat panel detector (FPD). Numerous pixels are arranged in the sensor panel and store charge upon receiving X-rays or radiation transmitted through the patient body. The sensor panel reads out the charge stored in the pixels, converts the charge into an image signal, and outputs a radiation image. The radiographic imaging device has the sensor panel, and also a memory and a communication interface. The memory stores the radiation image from the sensor panel in a temporary manner. The communication interface transmits the radiation image to the console device.
Well-known examples of the radiographic imaging device include an installed type and a portable type. The installed type is installed with a floor stand or patient table disposed in an examination room for radiographic imaging. The portable type has a portable housing and the sensor panel contained in the housing. The portable type of the radiographic imaging device is referred to as an electronic cassette for radiographic imaging. The electronic cassette as a mobile device can be carried to various locations in a hospital facility other than the examination room. For example, the electronic cassette is utilized for mobile imaging, namely, for imaging in a patient room for a patient who cannot walk to the examination room. Also, the electronic cassette may be used in various sites external to the hospital facility, for example, in a home of an elderly patient for home care services, in an emergency site of an accident or disaster where injury of a patient should be cared.
For the mobile imaging, a doctor, technician or operator positions the electronic cassette relative to the patient body, for example, sets the electronic cassette between the lying patient body and the bed, makes the patient hold the electronic cassette manually, or the like. Assuming that a cable is physically connected to the electronic cassette for communication with the console device, the cable is likely to obstruct smooth handling of the electronic cassette. In view of this problem, various ideas for wireless connection for the electronic cassette to the console device have been suggested, for example, in JP-A 2013-039322.
JP-A 2013-039322 discloses the radiographic imaging apparatus for radio communication between the electronic cassette and the console device. The disclosure of the document includes a method of preventing erroneous identification of the electronic cassette selected for the radiographic imaging and plural electronic cassettes different from the electronic cassette. For this purpose, the plural electronic cassettes are operated to measure their distances to the console device, by utilizing to strength of radio waves of the radio communication. One of the plural electronic cassettes that is the nearest to the console device is detected by evaluating the measured distances. Assuming that the nearest electronic cassette to the console device is different from the electronic cassette selected for the radiographic imaging, then alarm information is generated to inform the user or operator of possibility of erroneous identification of the electronic cassette.
The electronic cassette disclosed in JP-A 2013-039322 has a function of wirelessly communicating with the plural electronic cassettes located nearby. In the document, the electronic cassette selected for the radiographic imaging communicates with the plural electronic cassettes wirelessly. The plural electronic cassettes generate and transmit distance information to the electronic cassette being selected. The electronic cassette being selected generates and transmits the distance information of the plural electronic cassettes to the console device.
In case the electronic cassette is off-line from the console device in the course of transmitting the radiation image from the electronic cassette to the console device, then the radiation image remains stored in a memory of the electronic cassette until recovery of the communication. Assuming that the memory of the electronic cassette is short of an available memory space sufficient for storing a new radiation image, the radiographic imaging by use of the electronic cassette is impossible until the recovery of the communication. A problem arises in interruption in a workflow of the radiographic imaging. Efficiency in the radiographic imaging is considerably low, as waiting time on a side of the user or operator or the patient becomes long.